Chemical regulator the APVMA has banned the use of the insecticide omethoate on food crops.

ABC Rural: Tara De Landgrafft

A West Australian agronomist says soil health will suffer as a result of a ban by the chemical regulator the Australian Pesticides and Veterinary Medicines Authority (APVMA) on the use of the insecticide omethoate on food crops in Australia.

Omethoate is a broad-spectrum organophosphorus (OP) insecticide used to control insects and mites.

Citing concerns around toxicology, occupational health and safety and residues, the APVMA said the chemical would be phased out of Australia by December 2017.

The APVMA said the decision would have a minimal impact on farmers, and said it did extensive industry consultation on the decision.

Products containing omethoate will continue to be allowed for insect control on flowers, ornamentals and also as a barrier spray for controlling red-legged earth mite, but not in crop.

However omethoate products can no longer include uses in the home garden, on food producing plants, horticultural crops, pastures, grain legumes or cereals.

Esperance-based agronomist Luke Marquis said the ban would have an impact on grain growers bottom lines, and would also impact soil health.

He said the chemical was widely used for bryobia mite control in early canola crops, and was also used to control red legged earthmites in pasture paddocks.

"It's certainly, as far as red legged earthmite control in pastures, very important. It's part of an integrated approach," he said.

"Once you start banning some of these insecticides or products that are specific to certain insects, we are forced to go with more broad spectrum insecticides.

"We start putting on other products that will take out a wide range of insects, as well as the good insects."

He said removing beneficial insects would impact soil health and may require growers to use more chemicals.

"What we are striving to do as part of responsible integrated pest management is to actually keep beneficials in there," he said.

"If we are only taking out the specific pest and we leave the beneficials there, the beneficials will build in numbers and will try to keep a lot of the other smaller or minor pests under control.

"While a lot of the time we may not be able to quantify it exactly, we know in certain circumstances if we are keeping those beneficials there we can often get away with one spray and the beneficials are enough to keep those other pests under control.

"Some of these other insecticides we use they can hang around in the environment a lot longer, they'll often be known to wash into the soil and knock around things like earthworms etcetera, so it's certainly not ideal."

He said with omethoate out of the system, control costs would increase for farmers.

"Where we might be using say a $2 job with omethoate, we might be in the vicinity of $5 or $6 now, so it's just frustrating all round really," he said.

"I suppose in the scheme of a canola program it may not be a lot, but still it all adds up at the end of the day."